Mitochondrial DNA Variations and Their Impact on Aging

In recent research, it has been found that deletion mutations and aberrant expression of mitochondrial DNA (mtDNA) are correlated with biological ageing in humans and rodents (mammals).

---

About mtDNA

• Mitochondria are responsible for the synthesis of Adenosine Triphosphate (ATP) (the energy currency of cells).
• mtDNA encodes only a small subset of proteins required for mitochondrial function.
• Role of mtDNA in ageing: Age-related deletion mutations in mtDNA contribute to a decline in mitochondrial function, particularly in muscle cells.
• Many more mitochondrial proteins are encoded by the nuclear genome and enter the mitochondria after they are made in the part of the cell lying outside the mitochondrion and the nucleus (i.e. the cytoplasm).
• Individuals inherit their mitochondria exclusively from the mother via the egg cell.

 

Major Functions

• Energy Production: Produces ATP, required for muscle contraction, protein synthesis, and cell division.
• Cellular respiration: breakdown of food into energy in the form of ATP.
• Regulating Cell Health

 

Key Findings

• As we age, we lose bits of our genome in tissues such as the skeletal muscle and the brain.
• These losses known as deletion mutations, gradually erode the function of a cell component called the mitochondrion.
• Muscle cells lacking a sufficient number of functional mitochondria to support their contractile function die, and this causes a loss of muscle mass.